Simulating the total ionizing dose(TID)of an electrical system using transistor-level models can be difficult and expensive,particularly for digital-integrated circuits(ICs).In this study,a method for modeling TID eff...Simulating the total ionizing dose(TID)of an electrical system using transistor-level models can be difficult and expensive,particularly for digital-integrated circuits(ICs).In this study,a method for modeling TID effects in complementary metaloxide semiconductor(CMOS)digital ICs based on the input/output buffer information specification(IBIS)was proposed.The digital IC was first divided into three parts based on its internal structure:the input buffer,output buffer,and functional area.Each of these three parts was separately modeled.Using the IBIS model,the transistor V-I characteristic curves of the buffers were processed,and the physical parameters were extracted and modeled using VHDL-AMS.In the functional area,logic functions were modeled in VHDL according to the data sheet.A golden digital IC model was developed by combining the input buffer,output buffer,and functional area models.Furthermore,the golden ratio was reconstructed based on TID experimental data,enabling the assessment of TID effects on the threshold voltage,carrier mobility,and time series of the digital IC.TID experiments were conducted using a CMOS non-inverting multiplexer,NC7SZ157,and the results were compared with the simulation results,which showed that the relative errors were less than 2%at each dose point.This confirms the practicality and accuracy of the proposed modeling method.The TID effect model for digital ICs developed using this modeling technique includes both the logical function of the IC and changes in electrical properties and functional degradation impacted by TID,which has potential applications in the design of radiation-hardening tolerance in digital ICs.展开更多
A dynamics-based adaptive control approach is proposed for a planar dual-arm space robot in the presence of closed-loop constraints and uncertain inertial parameters of the payload. The controller is capable of contro...A dynamics-based adaptive control approach is proposed for a planar dual-arm space robot in the presence of closed-loop constraints and uncertain inertial parameters of the payload. The controller is capable of controlling the po- sition and attitude of both the satellite base and the payload grasped by the manipulator end effectors. The equations of motion in reduced-order form for the constrained system are derived by incorporating the constraint equations in terms of accelerations into Kane's equations of the unconstrained system. Model analysis shows that the resulting equations perfectly meet the requirement of adaptive controller design. Consequently, by using an indirect approach, an adaptive control scheme is proposed to accomplish position/attitude trajectory tracking control with the uncertain parameters be- ing estimated on-line. The actuator redundancy due to the closed-loop constraints is utilized to minimize a weighted norm of the joint torques. Global asymptotic stability is proven by using Lyapunov's method, and simulation results are also presented to demonstrate the effectiveness of the proposed approach.展开更多
Main sequence turn-off (MSTO) stars since their ages can be robustly estimated from have advantages as indicators of Galactic evolution atmospheric parameters. Hundreds of thousands of MSTO stars have been selected ...Main sequence turn-off (MSTO) stars since their ages can be robustly estimated from have advantages as indicators of Galactic evolution atmospheric parameters. Hundreds of thousands of MSTO stars have been selected from the LAMOST Galactic survey to study the evolution of the Galaxy, and it is vital to derive accurate stellar parameters. In this work, we select 150 MSTO star candidates from the MSTO star sample of Xiang that have asteroseismic parameters and determine accurate stellar parameters for these stars by combining asteroseismic parameters deduced from Kepler photometry and atmospheric parameters deduced from LAMOST spectra. With this sample, we examine the age determination as well as the contamination rate of the MSTO star sample. A comparison of age between this work and Xiang shows a mean difference of 0.53 Gyr (7%) and a dispersion of 2.71 Gyr (28%). The results show that 79 of the candidates are MSTO stars, while the others are contaminations from either main sequence or sub-giant stars. The contamination rate for the oldest stars is much higher than that for younger stars. The main cause for the high contamination rate is found to be the relatively large systematic bias in the LAMOST surface gravity estimates.展开更多
The FCSE controlling equation of pinned thinwalled curve box was derived and the indeterminate problem of continuous thin-walled curve box with diaphragm was solved based on flexibility theory. With Bayesian statistic...The FCSE controlling equation of pinned thinwalled curve box was derived and the indeterminate problem of continuous thin-walled curve box with diaphragm was solved based on flexibility theory. With Bayesian statistical theory,dynamic Bayesian error function of displacement parameters of indeterminate curve box was founded. The corresponding formulas of dynamic Bayesian expectation and variance were deduced. Combined with one-dimensional Fibonacci automatic search scheme of optimal step size,the Powell optimization theory was utilized to research the stochastic identification of displacement parameters of indeterminate thin-walled curve box. Then the identification steps were presented in detail and the corresponding calculation procedure was compiled. Through some classic examples,it is obtained that stochastic performances of systematic parameters and systematic responses are simultaneously deliberated in dynamic Bayesian error function. The one-dimensional optimization problem of the optimal step size is solved by adopting Fibonacci search method. And the Powell identification of displacement parameters of indeterminate thin-walled curve box has satisfied numerical stability and convergence,which demonstrates that the presented method and the compiled procedure are correct and reliable.During parameters鈥?iterative processes,the Powell theory is irrelevant with the calculation of finite curve strip element(FCSE) partial differentiation,which proves high computation effciency of the studied method.展开更多
Elemental analysis, Fourier transform infrared (FTIR), 1H-NMR, fluorescence spectroscopy, and surface tension methods have been used to characterize the molecular structure and the aggregation behaviors of two aspha...Elemental analysis, Fourier transform infrared (FTIR), 1H-NMR, fluorescence spectroscopy, and surface tension methods have been used to characterize the molecular structure and the aggregation behaviors of two asphaltenic fractions derived, respectively, from an Alge- rian petroleum well and a corresponding storage tank deposit. Elemental analysis, FTIR, ~H-NMR, and fluores- cence spectroscopy were used to investigate the chemical composition and structural parameters of asphaltenes, while the surface tension method was used to measure the critical micelle concentration (CMC) in organic solvents with different solubility parameters and polarities in order to characterize the asphaltenes' aggregation behaviors. Results show that the unstable asphaltenes fraction extracted from the storage tank deposit possesses a higher polarity (higher heteroatoms content) and a lower aro- maticity than stable asphaltenes from the petroleum well. The CMC results indicate that asphaltenes with high polarity and low aromaticity have a high solubility in polar solvents such as nitrobenzene, whereas asphaltenes with low polarity and high aromaticity are more soluble in solvents with weak polarity, like toluene. It is concludedthat the difference of structure of asphaltene samples and polarity of solvents can lead to difference of aggregation behaviors.展开更多
Lead has been recognized as a high risk toxic for most organisms including human. The effects of Pb in non-mammalian vertebrates are oprly known, particularly in anuran amphibians. The purpose of this study was to det...Lead has been recognized as a high risk toxic for most organisms including human. The effects of Pb in non-mammalian vertebrates are oprly known, particularly in anuran amphibians. The purpose of this study was to determine the effect of this metal on some hematological parameters of adult Bufo arenarum. It was found that all parameters remained unaltered within normal ranges, with the exception of reticulocyte counts which was significantly increased compared to the in controls (3. 7% vs. 0. 2 % ). It is suggested that the selective change found in reticulocyte count might be considered as an early response of a biomarker to sublethal exposition of Bufo arenarum to lead.展开更多
To identify target energy balance-related behaviors(ERBs),baseline data from 141overweight or obese schoolchildren(aged 8-14years old)was used to predict adiposity[body mass index(BMI)and fat percentage]one year...To identify target energy balance-related behaviors(ERBs),baseline data from 141overweight or obese schoolchildren(aged 8-14years old)was used to predict adiposity[body mass index(BMI)and fat percentage]one year later.The ERBs included a modified Dietary Approach to Stop Hypertension diet score(DASH score),leisure-time physical activity(PA,days/week),and leisure screen time(minutes/day).Several cardiometabolic variables were measured in the fasting state, including systolic blood pressure (SBP), diastolic blood pressure (DBP), blood glucose (GLU), total cholesterol (TC), triglycerides (TG), low-density lipoprotein (LDL-C), and high-density lipoprotein (HDL-C).展开更多
We present photometric observations in Sloan filters g′, i′of the eclipsing W UMa stars USNOA2.0 1350-17365531, V471 Cas, V479 Lac and V560 Lac. The sinusoidal-like O-C diagram of V471 Cas indicates the presence of ...We present photometric observations in Sloan filters g′, i′of the eclipsing W UMa stars USNOA2.0 1350-17365531, V471 Cas, V479 Lac and V560 Lac. The sinusoidal-like O-C diagram of V471 Cas indicates the presence of a third body with mass 0.12 M_⊙(a red dwarf) at distance 897 R_⊙. The O-C diagram of V479 Lac reveals a period decrease of d P/dt =-1.69 × 10-6d yr-1. The results of the light curve solutions are:(i) the targets are overcontact binaries with small fill-out factors;(ii) their components are F–K stars, comparable in size, whose temperature differences are below 80 K;(iii) all targets undergo partial eclipses and to limit the possible mass ratios we carried out two-step q-search analysis. The target global parameters(luminosities, radii, masses) were obtained on the basis of their Gaia distances and the results of our light curve solutions. The obtained total mass of V560 Lac turns out to be smaller than the lower mass limit for presently known W UMa binaries of 1.0-1.2 M_⊙, i.e. this target is a peculiar overcontact system.展开更多
We calculate photometric redshifts from the Sloan Digital Sky Survey Data Release 2 (SDSS DR2) Galaxy Sample using artificial neural networks (ANNs). Different input sets based on various parameters (e.g. magnitu...We calculate photometric redshifts from the Sloan Digital Sky Survey Data Release 2 (SDSS DR2) Galaxy Sample using artificial neural networks (ANNs). Different input sets based on various parameters (e.g. magnitude, color index, flux information) are explored. Mainly, parameters from broadband photometry are utilized and their performances in redshift prediction are compared. While any parameter may be easily incorporated in the input, our results indicate that using the dereddened magnitudes often produces more accurate photometric redshifts than using the Petrosian magnitudes or model magnitudes as input, but the model magnitudes are superior to the Petrosian magnitudes. Also, better performance resuits when more effective parameters are used in the training set. The method is tested on a sample of 79 346 galaxies from the SDSS DR2. When using 19 parameters based on the dereddened magnitudes, the rms error in redshift estimation is σz = 0.020184. The ANN is highly competitive tool compared to the traditional template-fitting methods when a large and representative training set is available.展开更多
We have investigated late time acceleration for a spatially fiat dust filled Universe in Brans- Dicke theory in the presence of a positive cosmological constant A. Expressions for Hubble's constant, luminosity distan...We have investigated late time acceleration for a spatially fiat dust filled Universe in Brans- Dicke theory in the presence of a positive cosmological constant A. Expressions for Hubble's constant, luminosity distance and apparent magnitude have been obtained for our model. The theoretical results are compared with observed values of the latest 287 high redshift (0.3 ≤ z ≤1.4) Type Ia supernova data taken from the Union 2.1 compilation to estimate present values of matter and dark energy parame- ters, (Ωm)0 and (ΩA)0. We have also estimated the present value of Hubble's constant H0 in light of an updated sample of Hubble parameter measurements including 19 independent data points. The results are found to be in good agreement with recent astrophysical observations. We also calculated various physical parameters such as matter and dark energy densities, present age of the Universe and decelera- tion parameter. The value for Brans-Dicke-coupling constant ω is set to be 40 000 based on accuracy of solar system tests and recent experimental evidence.展开更多
By simulating the electron paramagnetic resonance (EPR) and optical spectra on the basis of the 120 × 120 complete energy matrix, this paper determines the local lattice structure parameters R1 and R2 for MCl...By simulating the electron paramagnetic resonance (EPR) and optical spectra on the basis of the 120 × 120 complete energy matrix, this paper determines the local lattice structure parameters R1 and R2 for MCl:V2+ (M=Na, K, Rb) systems at 77K, 195 K and RT (room temperature 295 K or 302 K), respectively. The theoretical results indicate that there exists a compressed distortion in MCl:V2+ systems. Meanwhile, it finds that the structure parameters R1, R2 and |△R|( = R1 - R2) increase with the rising temperature. Subsequently, from the analysis it concludes that the relation of EPR parameter D vs. △R is approximately linear. Finally, the effects of orbital reduction factor k on the g factors for the three systems have been discussed.展开更多
BACKGROUND Carbon ion radiotherapy(CIRT)is currently used to treat prostate cancer.Rectal bleeding is a major cause of toxicity even with CIRT.However,to date,a correlation between the dose and volume parameters of th...BACKGROUND Carbon ion radiotherapy(CIRT)is currently used to treat prostate cancer.Rectal bleeding is a major cause of toxicity even with CIRT.However,to date,a correlation between the dose and volume parameters of the 12 fractions of CIRT for prostate cancer and rectal bleeding has not been shown.Similarly,the clinical risk factors for rectal bleeding were absent after 12 fractions of CIRT.AIM To identify the risk factors for rectal bleeding in 12 fractions of CIRT for prostate cancer.METHODS Among 259 patients who received 51.6 Gy[relative biological effectiveness(RBE)],in 12 fractions of CIRT,15 had grade 1(5.8%)and nine had grade 2 rectal bleeding(3.5%).The dose-volume parameters included the volume(cc)of the rectum irradiated with at least x Gy(RBE)(Vx)and the minimum dose in the most irradiated x cc normal rectal volume(Dx).RESULTS The mean values of D6cc,D2cc,V10 Gy(RBE),V20 Gy(RBE),V30 Gy(RBE),and V40 Gy(RBE)were significantly higher in the patients with rectal bleeding than in those without.The cutoff values were D6cc=34.34 Gy(RBE),D2cc=46.46 Gy(RBE),V10 Gy(RBE)=9.85 cc,V20 Gy(RBE)=7.00 cc,V30 Gy(RBE)=6.91 cc,and V40 Gy(RBE)=4.26 cc.The D2cc,V10 Gy(RBE),and V20 Gy(RBE)cutoff values were significant predictors of grade 2 rectal bleeding.CONCLUSION The above dose-volume parameters may serve as guidelines for preventing rectal bleeding after 12 fractions of CIRT for prostate cancer.展开更多
We study a general framework for assessing the injury probability corresponding to an input dose quantity. In many applications, the true value of input dose may not be directly measurable. Instead, the input dose is ...We study a general framework for assessing the injury probability corresponding to an input dose quantity. In many applications, the true value of input dose may not be directly measurable. Instead, the input dose is estimated from measurable/controllable quantities via numerical simulations using assumed representative parameter values. We aim at developing a simple modeling framework for accommodating all uncertainties, including the discrepancy between the estimated input dose and the true input dose. We first interpret the widely used logistic dose-injury model as the result of dose propagation uncertainty from input dose to target dose at the active site for injury where the binary outcome is completely determined by the target dose. We specify the symmetric logistic dose-injury function using two shape parameters: the median injury dose and the 10 - 90 percentile width. We relate the two shape parameters of injury function to the mean and standard deviation of the dose propagation uncertainty. We find 1) a larger total uncertainty will spread more the dose-response function, increasing the 10 - 90 percentile width and 2) a systematic over-estimate of the input dose will shift the injury probability toward the right along the estimated input dose. This framework provides a way of revising an established injury model for a particular test population to predict the injury model for a new population with different distributions of parameters that affect the dose propagation and dose estimation. In addition to modeling dose propagation uncertainty, we propose a new 3-parameter model to include the skewness of injury function. The proposed 3-parameter function form is based on shifted log-normal distribution of dose propagation uncertainty and is approximately invariant when other uncertainties are added. The proposed 3-parameter function form provides a framework for extending skewed injury model from a test population to a target population in application.展开更多
The inverse problem of wave equation is the importance of study not only in seismic prospecting but also in applied mathematics. With the development of the research, the inverse methods of 1 - D wave equations have b...The inverse problem of wave equation is the importance of study not only in seismic prospecting but also in applied mathematics. With the development of the research, the inverse methods of 1 - D wave equations have been trending towards the multiple parameters inversion . We have obtained an inverse method with double -parameter, in which medium density and wave velocity can be derived simultaneously. In this paper, to increase the inverse accuracy, the method is improved as follows. Firstly, the formula in which the Green Function is omitted are derived and used. Secondly, the regularizing method is reasonable used by choosing the stable function. With the new method, we may derive elastic parameter and medium density or medium density and wave velocity. Thus, lithology parameters for seismic prospecting may be obtained.After comparing the derived values from the new method with that from previous method, we obtain the new method through which substantially improve the derived accuracy . The new method has been applied to real depths inversion for sedimentary strata and volcanic rock strata in Chaoyanggou Terrace of Songliao Basin in eastern China. According to the inverse results,the gas - bearing beds are determlned.展开更多
A computer program MACA was developed for simulating high-dose ion implantation into amorphous solids. The topology of amorphous solids was modelled by adjusting the free flight path distribution between collisions, s...A computer program MACA was developed for simulating high-dose ion implantation into amorphous solids. The topology of amorphous solids was modelled by adjusting the free flight path distribution between collisions, so that the radial distribution function will characterize the short - range order and long - range disorder of amorphous targets. A simulation example is given.展开更多
The aim of this paper is to determinate the fundamental parameters of six exoplanet host (EH) stars and their planets. Because techniques for detecting exo- planets yield properties of the planet only as a function ...The aim of this paper is to determinate the fundamental parameters of six exoplanet host (EH) stars and their planets. Because techniques for detecting exo- planets yield properties of the planet only as a function of the properties of the host star, we must accurately determine the parameters of the EH stars first. For this rea- son, we constructed a grid of stellar models including diffusion and rotation-induced extra-mixing with given ranges of input parameters (i.e. mass, metallicity and initial rotation rate). In addition to the commonly used observational constraints such as the effective temperature Tell, luminosity L and metallicity [Fe/H], we added two obser- vational constraints, the lithium abundance log N (Li) and the rotational period Prot. These two additional observed parameters can set further constraints on the model due to their correlations with mass, age and other stellar properties. Hence, our estimations of the fundamental parameters for these EH stars and their planets have a higher preci- sion than previous works. Therefore, the combination of rotational period and lithium helps us to obtain more accurate parameters for stars, leading to an improvement in knowledge about the physical state of EH stars and their planets.展开更多
AIM: To describe our experience using a low-acceleratingdose regimen(LADR) with pegylated interferon alpha-2a and ribavirin in treatment of hepatitis C virus(HCV) recurrence. METHODS: From 2003, a protocolized LADR st...AIM: To describe our experience using a low-acceleratingdose regimen(LADR) with pegylated interferon alpha-2a and ribavirin in treatment of hepatitis C virus(HCV) recurrence. METHODS: From 2003, a protocolized LADR strategy was employed to treat liver transplant(LT) recipients with recurrent HCV at our institution. Medical records of 182 adult patients with recurrent HCV treated with LADR between 1/2003 and 1/2011 were reviewed. Histopathology from all post-LT liver biopsies were reviewed in a blinded fashion. Paired recipient and donor IL28 B status were assessed. A novel technique was employed to ascertain recipient and donor IL28B(rs12979860) Gt data using DNA extracted from archival FFPE tissue from explanted native livers and donor gallbladders respectively. The primary endpoint was SVR; secondary endpoints examined include(1) patient and graft survival;(2) effect of anti-viral therapy on liver histology(fibrosis and inflammation);(3) incidence of on-treatment development of ACR, CDR, or PCH;(4) association of recipient and donor IL28 B genotype with SVR; and(5) incidence of antiviral therapy-associated adverse events(anemia, leukopenia, thrombocytopenia, depression) and hepatic decompensation.RESULTS: The overall SVR rate was 38%(29% Gt1, 67% Gt2, 86% Gt3 and 58% Gt4). HCV Gt(P < 0.0001), donor age(P = 0.003), cytomegalovirus mismatch(P = 0.001), baseline serum bilirubin(P = 0.002), and baseline viral load(P = 0.04) were independent predictors for SVR. SVR rates were significantly higher in the recipient-CC/donor-non CC pairs(P = 0.007). Neither baseline fibrosis nor change in fibrosis stage after anti-viral therapy were associated with SVR. Fibrosis progressed in 72% of patients despite SVR. Median graft survival was 91 mo. Five-year patient survival was superior in patients who achieved SVR(97% vs 82%, P = 0.001). Pre-treatment ALP ≥ 150 U/L(P = 0.01), total bilirubin ≥ 1.5 mg/d L(P = 0.001) and creatinine ≥ 2 mg/d L(P = 0.001) were independently associated with patient survival. Only 13% of patients achieving SVR died during the followup period. Treatment discontinuation and treatmentrelated mortality occurred in 35% and 2.2% of patients, respectively. EPO, G-CSF and blood transfusion were needed in 89%, 40% and 23% of patients, respectively. Overall hospitalization rate for treatment-related serious adverse events was 21%. Forty-six(25%) of the patients were deceased; among those who died, 25(54%) were due to liver-related complications, and 4 deaths(9%) occurred while receiving therapy(2 patients experienced hepatic decompensation and 2 sepsis). CONCLUSION: LADR strategy remains relevant in managing post-LT recurrent HCV where access to DAAs is limited. SVR is associated with improved survival, but fibrosis progression still occurs.展开更多
This study aimed to investigate the dose-volume effects of γ-ray stereotactic body radiotherapy (SBRT) on clinical outcomes of patients with huge-size (≥10 cm) unresectable hepatocellular carcinoma (HCC). A total of...This study aimed to investigate the dose-volume effects of γ-ray stereotactic body radiotherapy (SBRT) on clinical outcomes of patients with huge-size (≥10 cm) unresectable hepatocellular carcinoma (HCC). A total of 59 patients with huge-size unresectable HCC were treated with SBRT following TACE between May 2006 and Dec. 2009. The analyzed parameters included fractional dose, marginal dose, maximal dose, and mean dose that the target received, as well as percentages of tumor volume encompassed by 60% (P<sub>60</sub>), 70% (P<sub>70</sub>), and 80% (P<sub>80</sub>) of isodose curves in entire tumor. The clinical outcomes included objective response rate (ORR), disease-free survival (DFS), overall survival (OS), and adverse event (AE). During median follow-up of 18.4 months, 81.4% of ORR (8.5% CR and 72.9% PR) was achieved, higher than 28.9% of ORR recently reported for TACE alone. 1- and 3-year DFS rates were 31.1% and 2.6% with median DFS of 8.7 months;1-, 3-, and 5-year OS rates were 46.5%, 13.7%, and 2.9%, with median OS of 11.8 months. P<sub>70</sub> was the only factor significantly correlating to DFS (P = 0.009) and OS (P = 0.01). Neither severe radiation-related liver disease nor > grade 3 AE was observed. In conclusion, SBRT was a safe and effective option for treatment of huge-size unresectable HCC. P<sub>70</sub> represented a parameter for predicting DFS and OS, and high dose-volume (e.g., P<sub>70</sub>) might be required to achieve improved clinical outcomes of patients with this type of HCC.展开更多
基金This work was supported by the special fund of the State Key Laboratory of Intense Pulsed Radiation Simulation and Effect(No.SKLIPR2011).
文摘Simulating the total ionizing dose(TID)of an electrical system using transistor-level models can be difficult and expensive,particularly for digital-integrated circuits(ICs).In this study,a method for modeling TID effects in complementary metaloxide semiconductor(CMOS)digital ICs based on the input/output buffer information specification(IBIS)was proposed.The digital IC was first divided into three parts based on its internal structure:the input buffer,output buffer,and functional area.Each of these three parts was separately modeled.Using the IBIS model,the transistor V-I characteristic curves of the buffers were processed,and the physical parameters were extracted and modeled using VHDL-AMS.In the functional area,logic functions were modeled in VHDL according to the data sheet.A golden digital IC model was developed by combining the input buffer,output buffer,and functional area models.Furthermore,the golden ratio was reconstructed based on TID experimental data,enabling the assessment of TID effects on the threshold voltage,carrier mobility,and time series of the digital IC.TID experiments were conducted using a CMOS non-inverting multiplexer,NC7SZ157,and the results were compared with the simulation results,which showed that the relative errors were less than 2%at each dose point.This confirms the practicality and accuracy of the proposed modeling method.The TID effect model for digital ICs developed using this modeling technique includes both the logical function of the IC and changes in electrical properties and functional degradation impacted by TID,which has potential applications in the design of radiation-hardening tolerance in digital ICs.
基金supported by the National Natural Science Foundation of China(11272027)
文摘A dynamics-based adaptive control approach is proposed for a planar dual-arm space robot in the presence of closed-loop constraints and uncertain inertial parameters of the payload. The controller is capable of controlling the po- sition and attitude of both the satellite base and the payload grasped by the manipulator end effectors. The equations of motion in reduced-order form for the constrained system are derived by incorporating the constraint equations in terms of accelerations into Kane's equations of the unconstrained system. Model analysis shows that the resulting equations perfectly meet the requirement of adaptive controller design. Consequently, by using an indirect approach, an adaptive control scheme is proposed to accomplish position/attitude trajectory tracking control with the uncertain parameters be- ing estimated on-line. The actuator redundancy due to the closed-loop constraints is utilized to minimize a weighted norm of the joint torques. Global asymptotic stability is proven by using Lyapunov's method, and simulation results are also presented to demonstrate the effectiveness of the proposed approach.
基金The Guoshoujing Telescope (the Large Sky Area Multi-Object Fiber Spectroscopic Telescope, LAMOST) is a National Major Scientific Project built by the Chinese Academy of Sciencesprovided by the National Development and Reform Commission+4 种基金National Astronomical Observatories, Chinese Academy of Sciencessupported by grants 11273007 and 10933002 from the National Natural Science Foundation of Chinathe Joint Research Fund in Astronomy (U1631236) under cooperative agreement between the National Natural Science Foundation of China (NSFC) and Chinese Academy of Sciences (CAS)the Fundamental Research Funds for the Central UniversitiesYouth Scholars Program of Beijing Normal University
文摘Main sequence turn-off (MSTO) stars since their ages can be robustly estimated from have advantages as indicators of Galactic evolution atmospheric parameters. Hundreds of thousands of MSTO stars have been selected from the LAMOST Galactic survey to study the evolution of the Galaxy, and it is vital to derive accurate stellar parameters. In this work, we select 150 MSTO star candidates from the MSTO star sample of Xiang that have asteroseismic parameters and determine accurate stellar parameters for these stars by combining asteroseismic parameters deduced from Kepler photometry and atmospheric parameters deduced from LAMOST spectra. With this sample, we examine the age determination as well as the contamination rate of the MSTO star sample. A comparison of age between this work and Xiang shows a mean difference of 0.53 Gyr (7%) and a dispersion of 2.71 Gyr (28%). The results show that 79 of the candidates are MSTO stars, while the others are contaminations from either main sequence or sub-giant stars. The contamination rate for the oldest stars is much higher than that for younger stars. The main cause for the high contamination rate is found to be the relatively large systematic bias in the LAMOST surface gravity estimates.
基金supported by the National Natural Science Foundation of China (10472045, 10772078 and 11072108)the Science Foundation of NUAA(S0851-013)
文摘The FCSE controlling equation of pinned thinwalled curve box was derived and the indeterminate problem of continuous thin-walled curve box with diaphragm was solved based on flexibility theory. With Bayesian statistical theory,dynamic Bayesian error function of displacement parameters of indeterminate curve box was founded. The corresponding formulas of dynamic Bayesian expectation and variance were deduced. Combined with one-dimensional Fibonacci automatic search scheme of optimal step size,the Powell optimization theory was utilized to research the stochastic identification of displacement parameters of indeterminate thin-walled curve box. Then the identification steps were presented in detail and the corresponding calculation procedure was compiled. Through some classic examples,it is obtained that stochastic performances of systematic parameters and systematic responses are simultaneously deliberated in dynamic Bayesian error function. The one-dimensional optimization problem of the optimal step size is solved by adopting Fibonacci search method. And the Powell identification of displacement parameters of indeterminate thin-walled curve box has satisfied numerical stability and convergence,which demonstrates that the presented method and the compiled procedure are correct and reliable.During parameters鈥?iterative processes,the Powell theory is irrelevant with the calculation of finite curve strip element(FCSE) partial differentiation,which proves high computation effciency of the studied method.
文摘Elemental analysis, Fourier transform infrared (FTIR), 1H-NMR, fluorescence spectroscopy, and surface tension methods have been used to characterize the molecular structure and the aggregation behaviors of two asphaltenic fractions derived, respectively, from an Alge- rian petroleum well and a corresponding storage tank deposit. Elemental analysis, FTIR, ~H-NMR, and fluores- cence spectroscopy were used to investigate the chemical composition and structural parameters of asphaltenes, while the surface tension method was used to measure the critical micelle concentration (CMC) in organic solvents with different solubility parameters and polarities in order to characterize the asphaltenes' aggregation behaviors. Results show that the unstable asphaltenes fraction extracted from the storage tank deposit possesses a higher polarity (higher heteroatoms content) and a lower aro- maticity than stable asphaltenes from the petroleum well. The CMC results indicate that asphaltenes with high polarity and low aromaticity have a high solubility in polar solvents such as nitrobenzene, whereas asphaltenes with low polarity and high aromaticity are more soluble in solvents with weak polarity, like toluene. It is concludedthat the difference of structure of asphaltene samples and polarity of solvents can lead to difference of aggregation behaviors.
文摘Lead has been recognized as a high risk toxic for most organisms including human. The effects of Pb in non-mammalian vertebrates are oprly known, particularly in anuran amphibians. The purpose of this study was to determine the effect of this metal on some hematological parameters of adult Bufo arenarum. It was found that all parameters remained unaltered within normal ranges, with the exception of reticulocyte counts which was significantly increased compared to the in controls (3. 7% vs. 0. 2 % ). It is suggested that the selective change found in reticulocyte count might be considered as an early response of a biomarker to sublethal exposition of Bufo arenarum to lead.
基金Research special fund of the Ministry of Health public service sectors funded projects(201202010)The 12th Five-year Key Project of Beijing Education Sciences Research Institute(AAA12011)
文摘To identify target energy balance-related behaviors(ERBs),baseline data from 141overweight or obese schoolchildren(aged 8-14years old)was used to predict adiposity[body mass index(BMI)and fat percentage]one year later.The ERBs included a modified Dietary Approach to Stop Hypertension diet score(DASH score),leisure-time physical activity(PA,days/week),and leisure screen time(minutes/day).Several cardiometabolic variables were measured in the fasting state, including systolic blood pressure (SBP), diastolic blood pressure (DBP), blood glucose (GLU), total cholesterol (TC), triglycerides (TG), low-density lipoprotein (LDL-C), and high-density lipoprotein (HDL-C).
基金supported partly by project DN08/20 of the Scientific Foundation of the Bulgarian Ministry of Education and Scienceby project RD 08-142 of Shumen University+1 种基金the support of the private IRIDA Observatory operated remotely(www.iridaobservatory.org)Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement
文摘We present photometric observations in Sloan filters g′, i′of the eclipsing W UMa stars USNOA2.0 1350-17365531, V471 Cas, V479 Lac and V560 Lac. The sinusoidal-like O-C diagram of V471 Cas indicates the presence of a third body with mass 0.12 M_⊙(a red dwarf) at distance 897 R_⊙. The O-C diagram of V479 Lac reveals a period decrease of d P/dt =-1.69 × 10-6d yr-1. The results of the light curve solutions are:(i) the targets are overcontact binaries with small fill-out factors;(ii) their components are F–K stars, comparable in size, whose temperature differences are below 80 K;(iii) all targets undergo partial eclipses and to limit the possible mass ratios we carried out two-step q-search analysis. The target global parameters(luminosities, radii, masses) were obtained on the basis of their Gaia distances and the results of our light curve solutions. The obtained total mass of V560 Lac turns out to be smaller than the lower mass limit for presently known W UMa binaries of 1.0-1.2 M_⊙, i.e. this target is a peculiar overcontact system.
基金the National Natural Science Foundation of China
文摘We calculate photometric redshifts from the Sloan Digital Sky Survey Data Release 2 (SDSS DR2) Galaxy Sample using artificial neural networks (ANNs). Different input sets based on various parameters (e.g. magnitude, color index, flux information) are explored. Mainly, parameters from broadband photometry are utilized and their performances in redshift prediction are compared. While any parameter may be easily incorporated in the input, our results indicate that using the dereddened magnitudes often produces more accurate photometric redshifts than using the Petrosian magnitudes or model magnitudes as input, but the model magnitudes are superior to the Petrosian magnitudes. Also, better performance resuits when more effective parameters are used in the training set. The method is tested on a sample of 79 346 galaxies from the SDSS DR2. When using 19 parameters based on the dereddened magnitudes, the rms error in redshift estimation is σz = 0.020184. The ANN is highly competitive tool compared to the traditional template-fitting methods when a large and representative training set is available.
基金supported by the CGCOST Research Project 789/CGCOST/MRP/14
文摘We have investigated late time acceleration for a spatially fiat dust filled Universe in Brans- Dicke theory in the presence of a positive cosmological constant A. Expressions for Hubble's constant, luminosity distance and apparent magnitude have been obtained for our model. The theoretical results are compared with observed values of the latest 287 high redshift (0.3 ≤ z ≤1.4) Type Ia supernova data taken from the Union 2.1 compilation to estimate present values of matter and dark energy parame- ters, (Ωm)0 and (ΩA)0. We have also estimated the present value of Hubble's constant H0 in light of an updated sample of Hubble parameter measurements including 19 independent data points. The results are found to be in good agreement with recent astrophysical observations. We also calculated various physical parameters such as matter and dark energy densities, present age of the Universe and decelera- tion parameter. The value for Brans-Dicke-coupling constant ω is set to be 40 000 based on accuracy of solar system tests and recent experimental evidence.
基金Project supported by the National Natural Science Foundation of China (Grant No 10774103)the Doctoral Education Fund of the Education Ministry of China (Grant No 20050610011)
文摘By simulating the electron paramagnetic resonance (EPR) and optical spectra on the basis of the 120 × 120 complete energy matrix, this paper determines the local lattice structure parameters R1 and R2 for MCl:V2+ (M=Na, K, Rb) systems at 77K, 195 K and RT (room temperature 295 K or 302 K), respectively. The theoretical results indicate that there exists a compressed distortion in MCl:V2+ systems. Meanwhile, it finds that the structure parameters R1, R2 and |△R|( = R1 - R2) increase with the rising temperature. Subsequently, from the analysis it concludes that the relation of EPR parameter D vs. △R is approximately linear. Finally, the effects of orbital reduction factor k on the g factors for the three systems have been discussed.
文摘BACKGROUND Carbon ion radiotherapy(CIRT)is currently used to treat prostate cancer.Rectal bleeding is a major cause of toxicity even with CIRT.However,to date,a correlation between the dose and volume parameters of the 12 fractions of CIRT for prostate cancer and rectal bleeding has not been shown.Similarly,the clinical risk factors for rectal bleeding were absent after 12 fractions of CIRT.AIM To identify the risk factors for rectal bleeding in 12 fractions of CIRT for prostate cancer.METHODS Among 259 patients who received 51.6 Gy[relative biological effectiveness(RBE)],in 12 fractions of CIRT,15 had grade 1(5.8%)and nine had grade 2 rectal bleeding(3.5%).The dose-volume parameters included the volume(cc)of the rectum irradiated with at least x Gy(RBE)(Vx)and the minimum dose in the most irradiated x cc normal rectal volume(Dx).RESULTS The mean values of D6cc,D2cc,V10 Gy(RBE),V20 Gy(RBE),V30 Gy(RBE),and V40 Gy(RBE)were significantly higher in the patients with rectal bleeding than in those without.The cutoff values were D6cc=34.34 Gy(RBE),D2cc=46.46 Gy(RBE),V10 Gy(RBE)=9.85 cc,V20 Gy(RBE)=7.00 cc,V30 Gy(RBE)=6.91 cc,and V40 Gy(RBE)=4.26 cc.The D2cc,V10 Gy(RBE),and V20 Gy(RBE)cutoff values were significant predictors of grade 2 rectal bleeding.CONCLUSION The above dose-volume parameters may serve as guidelines for preventing rectal bleeding after 12 fractions of CIRT for prostate cancer.
文摘We study a general framework for assessing the injury probability corresponding to an input dose quantity. In many applications, the true value of input dose may not be directly measurable. Instead, the input dose is estimated from measurable/controllable quantities via numerical simulations using assumed representative parameter values. We aim at developing a simple modeling framework for accommodating all uncertainties, including the discrepancy between the estimated input dose and the true input dose. We first interpret the widely used logistic dose-injury model as the result of dose propagation uncertainty from input dose to target dose at the active site for injury where the binary outcome is completely determined by the target dose. We specify the symmetric logistic dose-injury function using two shape parameters: the median injury dose and the 10 - 90 percentile width. We relate the two shape parameters of injury function to the mean and standard deviation of the dose propagation uncertainty. We find 1) a larger total uncertainty will spread more the dose-response function, increasing the 10 - 90 percentile width and 2) a systematic over-estimate of the input dose will shift the injury probability toward the right along the estimated input dose. This framework provides a way of revising an established injury model for a particular test population to predict the injury model for a new population with different distributions of parameters that affect the dose propagation and dose estimation. In addition to modeling dose propagation uncertainty, we propose a new 3-parameter model to include the skewness of injury function. The proposed 3-parameter function form is based on shifted log-normal distribution of dose propagation uncertainty and is approximately invariant when other uncertainties are added. The proposed 3-parameter function form provides a framework for extending skewed injury model from a test population to a target population in application.
文摘The inverse problem of wave equation is the importance of study not only in seismic prospecting but also in applied mathematics. With the development of the research, the inverse methods of 1 - D wave equations have been trending towards the multiple parameters inversion . We have obtained an inverse method with double -parameter, in which medium density and wave velocity can be derived simultaneously. In this paper, to increase the inverse accuracy, the method is improved as follows. Firstly, the formula in which the Green Function is omitted are derived and used. Secondly, the regularizing method is reasonable used by choosing the stable function. With the new method, we may derive elastic parameter and medium density or medium density and wave velocity. Thus, lithology parameters for seismic prospecting may be obtained.After comparing the derived values from the new method with that from previous method, we obtain the new method through which substantially improve the derived accuracy . The new method has been applied to real depths inversion for sedimentary strata and volcanic rock strata in Chaoyanggou Terrace of Songliao Basin in eastern China. According to the inverse results,the gas - bearing beds are determlned.
文摘A computer program MACA was developed for simulating high-dose ion implantation into amorphous solids. The topology of amorphous solids was modelled by adjusting the free flight path distribution between collisions, so that the radial distribution function will characterize the short - range order and long - range disorder of amorphous targets. A simulation example is given.
基金Supported by the National Natural Science Foundation of China
文摘The aim of this paper is to determinate the fundamental parameters of six exoplanet host (EH) stars and their planets. Because techniques for detecting exo- planets yield properties of the planet only as a function of the properties of the host star, we must accurately determine the parameters of the EH stars first. For this rea- son, we constructed a grid of stellar models including diffusion and rotation-induced extra-mixing with given ranges of input parameters (i.e. mass, metallicity and initial rotation rate). In addition to the commonly used observational constraints such as the effective temperature Tell, luminosity L and metallicity [Fe/H], we added two obser- vational constraints, the lithium abundance log N (Li) and the rotational period Prot. These two additional observed parameters can set further constraints on the model due to their correlations with mass, age and other stellar properties. Hence, our estimations of the fundamental parameters for these EH stars and their planets have a higher preci- sion than previous works. Therefore, the combination of rotational period and lithium helps us to obtain more accurate parameters for stars, leading to an improvement in knowledge about the physical state of EH stars and their planets.
基金Supported by JTD(an employee of Mount Sinai Medical Center)in part was provided by Genentech Pharmaceuticals
文摘AIM: To describe our experience using a low-acceleratingdose regimen(LADR) with pegylated interferon alpha-2a and ribavirin in treatment of hepatitis C virus(HCV) recurrence. METHODS: From 2003, a protocolized LADR strategy was employed to treat liver transplant(LT) recipients with recurrent HCV at our institution. Medical records of 182 adult patients with recurrent HCV treated with LADR between 1/2003 and 1/2011 were reviewed. Histopathology from all post-LT liver biopsies were reviewed in a blinded fashion. Paired recipient and donor IL28 B status were assessed. A novel technique was employed to ascertain recipient and donor IL28B(rs12979860) Gt data using DNA extracted from archival FFPE tissue from explanted native livers and donor gallbladders respectively. The primary endpoint was SVR; secondary endpoints examined include(1) patient and graft survival;(2) effect of anti-viral therapy on liver histology(fibrosis and inflammation);(3) incidence of on-treatment development of ACR, CDR, or PCH;(4) association of recipient and donor IL28 B genotype with SVR; and(5) incidence of antiviral therapy-associated adverse events(anemia, leukopenia, thrombocytopenia, depression) and hepatic decompensation.RESULTS: The overall SVR rate was 38%(29% Gt1, 67% Gt2, 86% Gt3 and 58% Gt4). HCV Gt(P < 0.0001), donor age(P = 0.003), cytomegalovirus mismatch(P = 0.001), baseline serum bilirubin(P = 0.002), and baseline viral load(P = 0.04) were independent predictors for SVR. SVR rates were significantly higher in the recipient-CC/donor-non CC pairs(P = 0.007). Neither baseline fibrosis nor change in fibrosis stage after anti-viral therapy were associated with SVR. Fibrosis progressed in 72% of patients despite SVR. Median graft survival was 91 mo. Five-year patient survival was superior in patients who achieved SVR(97% vs 82%, P = 0.001). Pre-treatment ALP ≥ 150 U/L(P = 0.01), total bilirubin ≥ 1.5 mg/d L(P = 0.001) and creatinine ≥ 2 mg/d L(P = 0.001) were independently associated with patient survival. Only 13% of patients achieving SVR died during the followup period. Treatment discontinuation and treatmentrelated mortality occurred in 35% and 2.2% of patients, respectively. EPO, G-CSF and blood transfusion were needed in 89%, 40% and 23% of patients, respectively. Overall hospitalization rate for treatment-related serious adverse events was 21%. Forty-six(25%) of the patients were deceased; among those who died, 25(54%) were due to liver-related complications, and 4 deaths(9%) occurred while receiving therapy(2 patients experienced hepatic decompensation and 2 sepsis). CONCLUSION: LADR strategy remains relevant in managing post-LT recurrent HCV where access to DAAs is limited. SVR is associated with improved survival, but fibrosis progression still occurs.
文摘This study aimed to investigate the dose-volume effects of γ-ray stereotactic body radiotherapy (SBRT) on clinical outcomes of patients with huge-size (≥10 cm) unresectable hepatocellular carcinoma (HCC). A total of 59 patients with huge-size unresectable HCC were treated with SBRT following TACE between May 2006 and Dec. 2009. The analyzed parameters included fractional dose, marginal dose, maximal dose, and mean dose that the target received, as well as percentages of tumor volume encompassed by 60% (P<sub>60</sub>), 70% (P<sub>70</sub>), and 80% (P<sub>80</sub>) of isodose curves in entire tumor. The clinical outcomes included objective response rate (ORR), disease-free survival (DFS), overall survival (OS), and adverse event (AE). During median follow-up of 18.4 months, 81.4% of ORR (8.5% CR and 72.9% PR) was achieved, higher than 28.9% of ORR recently reported for TACE alone. 1- and 3-year DFS rates were 31.1% and 2.6% with median DFS of 8.7 months;1-, 3-, and 5-year OS rates were 46.5%, 13.7%, and 2.9%, with median OS of 11.8 months. P<sub>70</sub> was the only factor significantly correlating to DFS (P = 0.009) and OS (P = 0.01). Neither severe radiation-related liver disease nor > grade 3 AE was observed. In conclusion, SBRT was a safe and effective option for treatment of huge-size unresectable HCC. P<sub>70</sub> represented a parameter for predicting DFS and OS, and high dose-volume (e.g., P<sub>70</sub>) might be required to achieve improved clinical outcomes of patients with this type of HCC.